1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2019 FORTH-ICS/CARV
4 * Nick Kossifidis <mick@ics.forth.gr>
5 */
6
7 #include <linux/kexec.h>
8 #include <asm/kexec.h> /* For riscv_kexec_* symbol defines */
9 #include <linux/smp.h> /* For smp_send_stop () */
10 #include <asm/cacheflush.h> /* For local_flush_icache_all() */
11 #include <asm/barrier.h> /* For smp_wmb() */
12 #include <asm/page.h> /* For PAGE_MASK */
13 #include <linux/libfdt.h> /* For fdt_check_header() */
14 #include <asm/set_memory.h> /* For set_memory_x() */
15 #include <linux/compiler.h> /* For unreachable() */
16 #include <linux/cpu.h> /* For cpu_down() */
17 #include <linux/reboot.h>
18
19 /*
20 * kexec_image_info - Print received image details
21 */
22 static void
kexec_image_info(const struct kimage * image)23 kexec_image_info(const struct kimage *image)
24 {
25 unsigned long i;
26
27 pr_debug("Kexec image info:\n");
28 pr_debug("\ttype: %d\n", image->type);
29 pr_debug("\tstart: %lx\n", image->start);
30 pr_debug("\thead: %lx\n", image->head);
31 pr_debug("\tnr_segments: %lu\n", image->nr_segments);
32
33 for (i = 0; i < image->nr_segments; i++) {
34 pr_debug("\t segment[%lu]: %016lx - %016lx", i,
35 image->segment[i].mem,
36 image->segment[i].mem + image->segment[i].memsz);
37 pr_debug("\t\t0x%lx bytes, %lu pages\n",
38 (unsigned long) image->segment[i].memsz,
39 (unsigned long) image->segment[i].memsz / PAGE_SIZE);
40 }
41 }
42
43 /*
44 * machine_kexec_prepare - Initialize kexec
45 *
46 * This function is called from do_kexec_load, when the user has
47 * provided us with an image to be loaded. Its goal is to validate
48 * the image and prepare the control code buffer as needed.
49 * Note that kimage_alloc_init has already been called and the
50 * control buffer has already been allocated.
51 */
52 int
machine_kexec_prepare(struct kimage * image)53 machine_kexec_prepare(struct kimage *image)
54 {
55 struct kimage_arch *internal = &image->arch;
56 struct fdt_header fdt = {0};
57 void *control_code_buffer = NULL;
58 unsigned int control_code_buffer_sz = 0;
59 int i = 0;
60
61 kexec_image_info(image);
62
63 /* Find the Flattened Device Tree and save its physical address */
64 for (i = 0; i < image->nr_segments; i++) {
65 if (image->segment[i].memsz <= sizeof(fdt))
66 continue;
67
68 if (copy_from_user(&fdt, image->segment[i].buf, sizeof(fdt)))
69 continue;
70
71 if (fdt_check_header(&fdt))
72 continue;
73
74 internal->fdt_addr = (unsigned long) image->segment[i].mem;
75 break;
76 }
77
78 if (!internal->fdt_addr) {
79 pr_err("Device tree not included in the provided image\n");
80 return -EINVAL;
81 }
82
83 /* Copy the assembler code for relocation to the control page */
84 if (image->type != KEXEC_TYPE_CRASH) {
85 control_code_buffer = page_address(image->control_code_page);
86 control_code_buffer_sz = page_size(image->control_code_page);
87
88 if (unlikely(riscv_kexec_relocate_size > control_code_buffer_sz)) {
89 pr_err("Relocation code doesn't fit within a control page\n");
90 return -EINVAL;
91 }
92
93 memcpy(control_code_buffer, riscv_kexec_relocate,
94 riscv_kexec_relocate_size);
95
96 /* Mark the control page executable */
97 set_memory_x((unsigned long) control_code_buffer, 1);
98 }
99
100 return 0;
101 }
102
103
104 /*
105 * machine_kexec_cleanup - Cleanup any leftovers from
106 * machine_kexec_prepare
107 *
108 * This function is called by kimage_free to handle any arch-specific
109 * allocations done on machine_kexec_prepare. Since we didn't do any
110 * allocations there, this is just an empty function. Note that the
111 * control buffer is freed by kimage_free.
112 */
113 void
machine_kexec_cleanup(struct kimage * image)114 machine_kexec_cleanup(struct kimage *image)
115 {
116 }
117
118
119 /*
120 * machine_shutdown - Prepare for a kexec reboot
121 *
122 * This function is called by kernel_kexec just before machine_kexec
123 * below. Its goal is to prepare the rest of the system (the other
124 * harts and possibly devices etc) for a kexec reboot.
125 */
machine_shutdown(void)126 void machine_shutdown(void)
127 {
128 /*
129 * No more interrupts on this hart
130 * until we are back up.
131 */
132 local_irq_disable();
133
134 #if defined(CONFIG_HOTPLUG_CPU)
135 smp_shutdown_nonboot_cpus(smp_processor_id());
136 #endif
137 }
138
139 /*
140 * machine_crash_shutdown - Prepare to kexec after a kernel crash
141 *
142 * This function is called by crash_kexec just before machine_kexec
143 * below and its goal is similar to machine_shutdown, but in case of
144 * a kernel crash. Since we don't handle such cases yet, this function
145 * is empty.
146 */
147 void
machine_crash_shutdown(struct pt_regs * regs)148 machine_crash_shutdown(struct pt_regs *regs)
149 {
150 crash_save_cpu(regs, smp_processor_id());
151 machine_shutdown();
152 pr_info("Starting crashdump kernel...\n");
153 }
154
155 /*
156 * machine_kexec - Jump to the loaded kimage
157 *
158 * This function is called by kernel_kexec which is called by the
159 * reboot system call when the reboot cmd is LINUX_REBOOT_CMD_KEXEC,
160 * or by crash_kernel which is called by the kernel's arch-specific
161 * trap handler in case of a kernel panic. It's the final stage of
162 * the kexec process where the pre-loaded kimage is ready to be
163 * executed. We assume at this point that all other harts are
164 * suspended and this hart will be the new boot hart.
165 */
166 void __noreturn
machine_kexec(struct kimage * image)167 machine_kexec(struct kimage *image)
168 {
169 struct kimage_arch *internal = &image->arch;
170 unsigned long jump_addr = (unsigned long) image->start;
171 unsigned long first_ind_entry = (unsigned long) &image->head;
172 unsigned long this_hart_id = raw_smp_processor_id();
173 unsigned long fdt_addr = internal->fdt_addr;
174 void *control_code_buffer = page_address(image->control_code_page);
175 riscv_kexec_method kexec_method = NULL;
176
177 if (image->type != KEXEC_TYPE_CRASH)
178 kexec_method = control_code_buffer;
179 else
180 kexec_method = (riscv_kexec_method) &riscv_kexec_norelocate;
181
182 pr_notice("Will call new kernel at %08lx from hart id %lx\n",
183 jump_addr, this_hart_id);
184 pr_notice("FDT image at %08lx\n", fdt_addr);
185
186 /* Make sure the relocation code is visible to the hart */
187 local_flush_icache_all();
188
189 /* Jump to the relocation code */
190 pr_notice("Bye...\n");
191 kexec_method(first_ind_entry, jump_addr, fdt_addr,
192 this_hart_id, kernel_map.va_pa_offset);
193 unreachable();
194 }
195